Device for producing a fibre mat by weaving

ABSTRACT

The invention relates to a device for producing a fibre mat by weaving, which fibre mat is built up of a substrate on which fibres are provided and which device is provided at least with means for forming a shed of warp yarns forming the substrate of the fibre mat, a lay as well as means disposed on one or both sides of the shed for inserting one or more weft yarns into the shed. The invention further relates to a fibre mat obtained by means of a device according to the invention.

FIELD OF INVENTION

The invention relates to a device for producing a fibre mat by weaving,which fibre mat is built up of a substrate on which fibres are providedand which device is provided at least with means for forming a shed ofwarp yarns forming the substrate of the fibre mat, a lay as well asmeans disposed on one or both sides of the shed for inserting one ormore weft yarns into the shed.

The invention also relates to a fibre mat obtained by using a deviceaccording to the invention.

BACKGROUND OF THE INVENTION

The term “fibre mat” as used in the present application is understood torefer to all kinds of substrates on which natural or synthetic fibresare provided, which fibre mats can be used for all kinds ofapplications, such as geotextile or, for example, as artificial grasssports fields or as so-called 3D mats or carpets.

Producing an artificial grass mat by means of a weaving technique is aproduction technique which has been developing the past few years inaddition to the known production techniques such as tufting or knitting.Weaving is to be preferred over tufting, since the tufting processinvariably takes place in a fixed pattern of rows or yarns. By using aweaving technique, it is possible to obtain a semi-random pattern in theshed by means of the reeds, which makes the fibre mat, for example anartificial grass mat, look better and gives it a natural appearance.

Furthermore, weaving is a simpler technique than tufting. In tufting,the substrate is woven first, and subsequently the fibres are tufted.

SUMMARY OF THE INVENTION

The object of the invention is to provide an improved technique forproducing a fibre mat and to provide a device for producing a fibre matby using a weaving technique, which makes it possible, using oneprocessing step, to obtain a fabric comprising free upright syntheticfibres having a semi-random, variable and adjustable pile height.

According to the invention, the device is characterised in that thedevice is provided with cutting means for cutting one or more weft yarnsthrough in one or more places. In this way it is possible to create thefree upright synthetic fibres in the fabric during the weaving stepalready, making it possible to obtain a fibre mat having a variable,adjustable pile height, which simulates a natural lawn, for example.

According to another embodiment, the device is characterised in that thecutting means are disposed downstream of the shed. This makes itpossible to obtain free upright synthetic fibres already during theweaving step. In this way the need for an additional processing step ofthe fabric obtained after the weaving step is obviated, which simplifiesthe operation and which speeds up the production process considerably.

According to a functional aspect of the invention, the device ischaracterised in that the cutting means comprise at least one knifeelement. More in particular, the cutting surface of said at least oneknife element extends perpendicularly to the insertion direction of theweft yarn. This aspect makes it possible to cut the weft yarn through atthe desired position already during the weaving process so as to obtainfree upright synthetic fibres.

According to another functional aspect of the invention, the device ischaracterised in that said at least one knife element is fixedlydisposed, whilst in another embodiment said at least one knife elementis movably disposed. Said at least one knife element can conduct ascissor movement.

In another moving embodiment it is preferable if said at least one knifeelement is rotatable, with the cutting means more in particularcomprising at least one rotatably driven shaft provided with severalspaced-apart knife elements. Thus the weft yarns can be cut through inan efficient and quick manner during the weaving process so as to obtainupright synthetic fibres.

In order to be able to set the pile height of the separate uprightsynthetic fibres, the spacing between the knife elements is according tothe invention adjustable.

According to the invention, in order to realize a reliable cuttingthrough of the weft yarns at the desired positions, the device comprisessupport means for the weft yarns, which support means cooperate with thecutting means.

More in particular, in a specific embodiment the support means compriseat least one rod member, over which the weft yarns to be cut through canbe passed. Said rod member may be provided with a recess which iscapable of receiving at least part of the cutting element.

In order to realise an effective insertion of the weft yarns in thedirection of the cutting means, the device is according to a specificaspect of the invention characterised in that the support means compriseat least one wire-like support guide supporting the weft yarns, whichwire-like support guide is connected to the free end of a rod memberwith a first end and to the device with another end. The free end of therod member may furthermore be screw-connected to the rod member,enabling easy mounting of the wire-like support guide.

In this way only the weft yarns that are to be cut through are led inthe direction of the cutting means, whilst the weft yarns not to be cutthrough by the knife element in question can be guided past the cuttingmeans in question without being cut.

In a functional embodiment, the device is characterised in that thewire-like support guide is connected to the device with its other end bymeans of a spring element. By having the wire-like support guide formpart of the moving shed, a weft yarn to be cut through by the respectivecorresponding cutting element can thus be guided over the wire-likesupport guide device of the knife element.

Furthermore, the support means may be tiltable relative to the shed,which prevents the weft yarns from undesirable jamming or getting caughton the free end of the rod member. This also increases the tension onthe weft yarns and thus facilitating the cutting action of the weftyarns through the cutting elements.

According to a functional aspect of the device according to theinvention, the wire-like support guide is made of a plastic or a metal.

In two other functional embodiments, the cutting means can cut said oneor more weft yarns through in one or more places using ultrasound orheat.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail in the description ofthe figures below, in which reference is made to a drawing, in which:

FIG. 1 shows a first view of a device according to the invention;

FIGS. 2-8 show further views of the device according to FIG. 1;

FIGS. 9, 10 a-10 b show examples of a layout of a fibre mat obtained bymeans of the device according to the invention.

For a better understanding of the invention, like parts will beindicated by identical numerals in the description of the figures below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It should be noted that the fibre mat as described in the present patentapplication may be embodied in various ways, for example as a fibre matfor use in landscaping (for example for supporting dike bodies) or asfibre mats purely having a sports function, such as an artificial grassmat for soccer fields or hockey fields. Such a weaving device isprovided with means 10 forming a shed or reed for warp yarns 20 beingfed to the shed from behind the weaving device.

A fibre mat as described in the present application may comprise naturalfibres as well as synthetic fibres.

The lay 10 functions to keep the warp yarns some distance apart and alsoto weave weft yarns 21 alternately between the various weft yarns. Thewarp yarns 20 thus form the substrate of the fibre mat.

To insert the weft yarns 21, insertion means 11 are disposed on one sideof the shed, which insertion means unwind the weft yarns 21 from asupply bobbin (not shown) and weave them between the various warp yarns20 in the shed 10 by means of a projectile reciprocating through theshed, for example a gripper, or by means of air or water.

A fibre mat consists of a substrate on which synthetic fibres areprovided. The synthetic fibres have a certain pile height and extendupwards from the substrate so as to make the fibre mat look more likenatural grass in those cases in which the fibre mat is intended for useas a geotextile mat or an artificial grass mat. Usually, an infillmaterial, for example consisting of said and/or small particles of asynthetic material (for example rubber), is provided between the uprightfibres. During the process of weaving, the weft yarns of the fibre mat,which eventually are to form also the upright fibres in the final fibremat, have been fully inserted between the warp yarns 20.

According to the invention, in order to realise a fibre mat with freeupright synthetic fibres, cutting means 30 (see FIG. 2) are provided,which cut the various weft yarns 21 through in one or more places in theshed 10.

As is clearly shown in FIG. 2 (and FIGS. 3-4-5), the cutting means 30consist of a shaft 34, which is mounted to a frame 39 forming part ofthe weaving device by means of support flanges 35. The support shaft 34can be rotatably driven by a drive unit 36 (for example an electricmotor) which rotatably drives the support shaft 34 via a gear 36 a, atransmission carrier 37 and a gear 38. Also other ways of driving theshaft by means of a chain or another type of endless carrier arepossible, however.

According to the invention, cutting elements 33 are provided somedistance apart on the support shaft 34, said cutting elements in thisembodiment being embodied as rotatably driven knives 33. The knifeelements 33 can be rotatably driven by means of the support shaft 34, tobe true, but they are further fixedly disposed relative to the frame 39(and the weaving device 10). During the weaving process, the fibre mat(substrate of warp yarns 20 with inserted weft yarns 21) thus wovenmoves from the shed in the direction of the frame 39 and the cuttingmeans 30.

The rotating cutting elements cut the weft yarns 21 through atpredetermined positions, so that a free upright end can function as aartificial grass fibre. The rest of the weft yarn thus remains presentin the substrate 20 as a part woven into said substrate, so that theartificial grass fibre cannot undesirably become detached from thesubstrate 20 without a force (for example a pulling force) beingexerted.

It should be noted that the cutting means can also be realised in otherembodiments, for example in the form of non-moving, rigidly disposedknife elements, past which the weft yarn is carried. In anotherembodiment, the knife elements may be configured as small scissors whichare driven in a suitable manner.

The cutting means may also be oriented perpendicularly to the insertiondirection of the weft yarn, as is shown in the figures. An improvedcutting action can be realised, however, if the cutting means aredisposed at an angle to the insertion direction of the weft yarn 21.

To achieve a correct cutting of the weft yarns 21 so as to obtainsynthetic fibres having a desired pile height, the weaving deviceaccording to the invention is provided with support means whichcooperate with the various cutting elements 23. The support means areindicated at 23, being configured as rod members 32 which are rigidlyconnected to the frame 39.

The function of the rod members 32 is a passive one performed by thefree ends 32 a, which lift the weft yarns to be cut through and guidesaid weft yarns over the rod member 32 in the direction of the cuttingelements 33. Weft yarns 21 not to be cut through are passed under therod member 32 and are thus not cut through by the corresponding cuttingelement 33 but remain unaffected, being woven in between the warp yarns20. Thus a suitable fixation in the warp yarns 20 of the separate weftyarns functioning as artificial grass fibres is guaranteed.

To achieve an expert, trouble-free cutting of the weft yarns 21 by thecutting elements 33, each rod member 32 may be provided with a recess 32b capable of receiving at least part of the cutting surface 33 a of eachcutting element.

Preferably, the free end 32 a of each rod member 32 can be screwed ontothe rod member 32 by means of a screw thread 32 c. The free end 32 maybe hollow and be provided with an opening 32 d, through which awire-like support guide 31 (see FIGS. 2, 7 and 8) extends, whichwire-like support guide is connected to the free end of the rod member32 with one end and to the device with the other end.

As FIGS. 1, 2, 7 and 8 clearly show, the wire-like support guides 31 areguided through the shed and the reed 10 to the side of the weavingdevice where the weft yarns 21 are inserted into the weaving device. Thewire-like support guides 31 are reciprocated through the shed by theinsertion means of the weaving device, so that, depending on the weavingaction, weft yarns 21 are inserted into the shed below and above thewire-like support guides.

The support guides are preferably tiltably mounted in the device, thuspreventing the weft yarns from undesirable jamming or getting caught onthe free end thereof. The support beam 39 is to that end tiltablerelative to the shed. The support beam 39 may for example be connectedto an eccentric transmission, which transmission can be driven from theweaving device.

Since each wire-like support guide 31 is connected to a rod member 32,the weft yarns 21 inserted over the wire-like support guide 31 inquestion will irrevocably be carried in the direction of the associatedcutting element 33 to be cut through there.

Weft yarns 21 that have been locally inserted under a wire-like supportguide 31 will thus not be cut through at the location of said wire-likesupport guide (and the rod member 32 and the knife element 33,respectively).

As FIG. 8 clearly shows, the various wire-like support guides 31 areconnected to a support beam 10 a of the weaving device with their otherend 31 b, preferably by means of a spring element 40, so that movementsand stresses in the wire-like support guide 31, which stresses candevelop during the weaving process, can be absorbed in a simple manner.

By tilting the support guides, as stated above, not only an undesirablejamming of the weft yarns is prevented. In combination with the springelements 40, the tilting of the rods 32 immediately lifts the wire likesupport guides 31, hence lifting the weft yarns guided by these wires tothe rods increasing the tension on the weft yarns and thus facilitatingthe cutting action of the weft yarns through the cutting elements.

Below, the parameters of a fibre mat obtained by means of a deviceaccording to the invention will be described by way of example. Such afibre mat is shown in FIG. 9, in which the numerals in the row ofnumerals beside the shed (or reed) 10 refer to the weft yarns 20. Thefigure clearly shows the freely projecting artificial grass fibres 21a-21 b obtained by locally cutting through the weft yarns 21 in thefibre mat, using the cutting means 30. The fibre mat (or fibre carpet)has a surface density of 1265 g/m², consisting of a yarn of 8300 DTEX.The number of picks per centimetre is 14.5, whilst the pile height ofthe synthetic fibres 21 a-21 b cut free is about 60 mm.

In FIGS. 10 a-10 b a different layout of a fibre mat is disclosed, withreference X indicating the position where the weft yarn is cut throughby the cutting means 30 for obtaining individual synthetic fibres.

The mat has been woven in accordance with the following construction: 20weft yarns flat+10 warp yarns tied off with at least one double W-knot.However, the weaving device may also be configured to weave with 2-25weft yarns flat+2-50 warp yarns tied off with at least one doubleW-knot.

The fibre mats that can be produced by means of the device according tothe invention are in particular suitable for use as a geotextile inlandscaping, but they can also be used for (soccer) sports fields.Characteristic of such fibre mats is the fact that use is made of atwo-dimensional weaving technique, by means of which a functional 3D(artificial grass) construction is realised.

1. A device for producing a fibre mat by weaving, which fibre mat isbuilt up of a substrate on which fibres are provided and which device isprovided at least with means for forming a shed of warp yarns formingthe substrate of the fibre mat, a lay as well as means disposed on oneor both sides of the shed for inserting one or more weft yarns into theshed, wherein the device is provided with cutting means for cutting oneor more weft yarns through in one or more places.
 2. A device accordingto claim 1, wherein the cutting means are disposed downstream of theshed.
 3. A device according to claim 1, wherein the cutting meanscomprise at least one knife element.
 4. A device according to claim 3,wherein the cutting surface of said at least one knife element extendsperpendicularly to the insertion direction of the weft yarn.
 5. A deviceaccording to claim 3, wherein the cutting surface of said at least oneknife element extends at an angle to the insertion direction of the weftyarn.
 6. A device according to claim 3, wherein said at least one knifeelement is fixedly disposed.
 7. A device according to claim 3, whereinsaid at least one knife element is movably disposed.
 8. A deviceaccording to claim 7, wherein said at least one knife element conducts ascissor movement.
 9. A device according to claim 7, wherein said atleast one knife element is rotatable.
 10. A device according to claim 9,wherein the cutting means comprise at least one rotatably driven shaftprovided with several spaced-apart knife elements.
 11. A deviceaccording to claim 10, wherein the spacing between said knife elementsis adjustable.
 12. A device according to claim 1, wherein the devicecomprises support means for the weft yarns, which support meanscooperate with the cutting means.
 13. A device according to claim 12,wherein the support means comprise at least one rod member, over whichthe weft yarns to be cut through can be passed.
 14. A device accordingto claim 13, wherein said rod member is provided with a recess which iscapable of receiving at least part of the cutting element.
 15. A deviceaccording to claim 12, wherein the support means comprise at least onewire-like support guide supporting the weft yarns, which wire-likesupport guide is connected to the free end of a rod member with a firstend and to the lay with another end.
 16. A device according to claim 15,wherein the free end of said rod member is screw-connected to said rodmember.
 17. A device according to claim 15, wherein said wire-likesupport guide is connected to the device with its other end by means ofa spring element.
 18. A device according to claim 12, wherein saidsupport means are tiltable relative to the shed.
 19. A device accordingto claim 15, wherein said wire-like support guide is made of a plasticmaterial.
 20. A device according to claim 15, wherein said wire-likesupport guide is made of a metal.
 21. A device according to claim 1,wherein said cutting means cut said one or more weft yarns through inone or more places using ultrasound.
 22. A device according to claim 1,wherein said cutting means cut said one or more weft yarns through inone or more places using heat.
 23. A fibre mat obtained by means of thedevice according to one or more of the preceding claims.